Two different anionic manganese(II) coordination polymers constructed through dicyanamide coordination bridges

Abstract

In order to explore new metal coordination polymers and to search for new types of ferroelectrics among hybrid coordination polymers, two manganese dicyanamide complexes, poly[tetramethylammonium [di-μ3-dicyanamido-κ(6)N(1):N(3):N(5)-tri-μ2-dicyanamido-κ(6)N(1):N(5)-dimanganese(II)]], {[(CH3)4N][Mn2(NCNCN)5]}n, (I), and catena-poly[bis(butyltriphenylphosphonium) [[(dicyanamido-κN(1))manganese(II)]-di-μ2-dicyanamido-κ(4)N(1):N(5)]], {[(C4H9)(C6H5)3P]2[Mn(NCNCN)4]}n, (II), were synthesized in aqueous solution. In (I), one Mn(II) cation is octahedrally coordinated by six nitrile N atoms from six anionic dicyanamide (dca) ligands, while the second Mn(II) cation is coordinated by four nitrile N atoms and two amide N atoms from six anionic dca ligands. Neighbouring Mn(II) cations are linked together by μ-1,5- and μ-1,3,5-bridging dca anions to form a three-dimensional polymeric structure. The anionic framework exhibits a solvent-accessible void of 289.8 Å(3), amounting to 28.0% of the total unit-cell volume. Each of the cavities in the network is occupied by only one tetramethylammonium cation. In (II), each Mn(II) cation is octahedrally coordinated by six nitrile N atoms from six dca ligands. Neighbouring Mn(II) cations are linked together by double dca bridges to form a one-dimensional polymeric chain, and C-H...N hydrogen-bonding interactions are involved in the formation of the one-dimensional layer structure.